Potential security issue with the pattern unlockGeneral

Most people will probably never notice this or never care, but here's what I noticed.

If you unlock the screen and make a call, and don't use the touchscreen much at all, someone can pick up the phone and look at the smudges on the screen and see your unlock pattern. I tried this with my daughters phone earlier and was able to unlock it without previously knowing her code.

I guess the tip is to wipe the screen off before you leave it unattended.

Or use a pattern that overlaps itself (using the same vertex more than once) so that they can't tell what direction you went...

For example, if you just make a non-overlapping line, though, there's only 2 possible starting places and each one determines the direction of travel. So, if you can see the squiggle, you can break in with only 2 tries.

But, if you use a full circle, there's 8 possible starting places, and two possible directions of travel. That requires 16 tries.